The present invention relates in general to a stimulator system and, more particular, to an electrical stimulator system having a rechargeable potential source, i.e., a battery, for generating electrical stimulating pulses for the stimulation of a muscle, nerve or the like in the treatment of incontinence. More specifically, the present invention provides an electrical stimulator system suitable for use with rechargeable batteries in accordance with what is customary in other areas where rechargeable batteries are used for driving different devices such as calculators or the like. In this regard, the present invention takes into consideration the special problems which are associated with electrical stimulation for the treatment of incontinence and, more particular, with vaginal and anal stimulation.
One such electrical stimulator system is disclosed in U.S. Pat. No. 4,106,511 which includes an obturator intended to be worn within the vagina or anus. The obturator is provided with electrodes energized by a pulse generator for controlling the urethra, bladder and/or rectal functions of the wearer. However, such prior art stimulator system is constructed to use disposable batteries as a potential source for supplying power to the pulse generator. When the batteries become sufficiently discharged during use, it is required that the wearer replace these batteries before continued use is possible. It is readily apparent that the necessity for periodic replacement of such batteries presents a number of disadvantages, e.g., economic and convenience, in electrical stimulator systems of this known prior art type.
In U.S. Pat. No. 3,902,502, there is disclosed a stimulator system for temporarily arresting arthritic pain which incorporates a rechargeable battery adapted to be charged by an external charging device. When the rechargeable batteries become discharged during use, the charging device is alternatively connected to the system's common output terminals for charging the batteries through a charging circuit provided therein. A diode is provided to prevent current from the charging device from flowing through other than the charging circuit during charging of the system's batteries. However, this charging circuit arrangement is not adapted for use where the current is required to be transmissible in both directions, i.e., bipolar pulses as the diode element is adapted for use with monopolar pulses in permitting current to flow in only one direction. Further, this prior art system is not suitable for use where the system's output voltage is higher than the battery voltage. In this regard, a higher output voltage would be short circuited directly to the battery through the charging circuit.